Rotary engine.



PATENTED Nov. 7, 1905.

.W. M. HOFFMAN.

ROTARY ENGINE.

APPLICATION FILED mmzs, 1905.

Z SHEETS-SKEET l- ZZZ/anion PATENTED NOV. 7, 1905.

W. M. HOFFMAN.

ROTARY ENGINE.

APPLICATION rum) MAB..25, 1905.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

ROTARY ENGINE.

Specification of Letters Patent.

Patented Nov. '7, 1905.

Application filed March 25, 1905. Serial No. 251,964.

To all whom it may concern.-

7 Be it known that 1, WILLIAM M. HOFFMAN, a citizen of the UnitedStates, residing at Buffalo, in the county of Erie and State of NewYork, have invented a new and useful 1mprovement in Rotary Engines, ofwhich the following is a specification.

This invention relates to rotary engines of that kind comprising arotatable cylinder or casing, a core arranged within the cylinder orcasing to rotate with the cylinder about an axis eccentric .to theaxisof the cylinder, and pistons or blades which cross the space betweenthe cylinder and core and against which the steam or other motive fluidexerts its pressure to drive the engine.

The object of the invention is to produce a rotary engine of greatefficiency and economy in which friction and wear are reduced to theminimum and to simplify the construction and reduce the numberof'necessary parts of a rotary engine.

In the accompanying drawings, consisting of two sheets, Figure 1 is alongitudinal sectional elevation of a rotary engine embodying theinvention. Fig. 2 is a transverse sectional elevation thereof in line 22, Fig. 1. Fig. 3 is a perspective view of three sections of the core,the sections being separated somewhat to better show their shape. Fig. 4is a transverse sectional elevation of the engine in line 4 4, Fig. 1.Fig. 5 is a transverse sectional elevation thereof in line 5 5, Fig. 1.

Like characters of reference refer to like parts in the several figures.

A represents the cylinder or hollow cylindrical casing, which may be ofany suitable construction and is rotatably mounted in any desiredmanner. The cylinder shown consists of a cylindrical shell or body andheads a a, bolted to the ends of the body, one of the heads a beinghollow and serving as a steam-chest. This cylinder is journaledcentrally on'and rotates about a stationary shaft B, supported inbearing-standards b or in any other desired way.

0 represents the core, which is located inthe cylinder, extending fromhead to head thereof, and is journaled to rotate about an axis eccentricto that of the cylinder. The core consists of sector-shaped longitudinalsections provided with hubs or bearing-rings c at their inner ends whichencircle the eccentric journal 0 for the core. This journal maybeformed, as shown, by an eccentric or crank portion of the stationaryshaft B. The

'between the core-sections.

bearing-rings c are located at different points longitudinally on theseveral sections, so that they bear side to side against each other onthe journal. The core-sections are narrow enough to oscillate toward andfrom each other on their journal as they rotate about the same, and eachcore-section has at its outer portion a segmental tail or extension 0 gwhich overlaps and slides on the next coresection, thus closing thesector-shaped space The circular outer face of each core-section isrecessed at c for the reception of the extension of the adjacentsection.

D represents the pistons or blades against which the steam or othermotive fluid admitted to the space between the cylinder and core exertsits pressure to drive the engine. These pistonsproject inwardly from thecircular wall of the cylinder in substantially radial lines and extendfrom head to head of the cylinder, to which they are bolted or otherwiseimmovably fixed. Each piston extends into a pocket E in one of thecore-sections and has a rocking bearing therein,- preferably formed bysegmental cylindrical blocks f, arranged at opposite sides of the pistonand confined in correspondingly-shaped seats in the piston-pocket E ofthe core. The pistons cause the core to rotate with the cylinder, andthe rocking bearing-blocks f allow the core-sections to approach andrecede from each other and also to approach and recede from successiveportions of the inner periphery of the cylinder as the core and cylinderrevolve. The blades being fixed to the cylinder can be tightly fitted,and no packing is required between the pistons and the cylinder, and therocking blocks f for the pistons are wedged in their seats against theopposite faces of the pistons by steam-pressure thereon and efiicientl ypack the pistons, so as to prevent leakage of steam into thepiston-pockets E in the core.

In the engine illustrated in the drawings the several core-sections aredivided transversely into halves 1 and 2, (see Fig. 1,) which are forcedoppositely into close contact with the heads of the cylinder by springsg between the halves. This construction avoids the necessity for packingthe ends of the core. The halves of the core-sections are'tongued andgrooved together, as shown at g, and are recessed inside of the tonguesand grooves to receive packing-strips g Figs. 1 and 5. This making ofthe core-sections in halves, while deemed preferable, is in no sense anecessary feature of the construction of the core, the sections of whichcould manifestly be continuous from head to head of the cylinder. It hasnot been thought necessary to further describe the manner of packing theseveral parts of the engine, as this may be accomplished in differentways, and a description thereof would to enable an understanding of theengine.

The steam is admitted to the steam-chest a through a passage it and portit in one end of the stationary shaft B. The inner wall of the hollowhead or steam-chest is provided with inlet-passages t', opening at oneend into the steam-chest and at the other end into the cylinder just inrear of the pistons D. I is a disk-valve which is located in thesteam-chest and held from turning on the stationary shaft, but ismovable longitudinally on the shaft and held by steam-pressure againstthe inner wall of the steam-chest a, which has the inlet-passages 11.The valve-disk has an ad mission-port z" of suitable length, with whichthe inlet-passages successively register as the cylinder rotates andwhich admits steam to each inletpassage t' during a part revolution ofthe cylinder or while the passage is passing the port in the valve.

K represents an exhaust-passage in the stationary shaft, and Ir ports inthe eccentric journal for the core connecting with said passage. Eachcore-section is provided with one or more exhaust-passages lo, extendingradially therethrough and adapted in the rotation of the core toregister with the ports L" in the journal to connect the steam-spacebetween the core and cylinder with the exhaustpassage K. The tail ofeach coresection, which slides over the exhaust-passages 7: in theadjacent core-section, has a hole to register with the passages 70, soas not to close them. As each core-section is forced inwardly and heldin close contact with the journal by the steam-pressure, there is noleakage or escape of the steam through the exhaust-passages ]c of thecore-sections until they register with the exhaustports of the journal.The cylinder of the engine is the driving part, and power may betransmitted therefrom by a pulley L, secured to one of the hubs of thecylinder, which is extended for this purpose, or in any other suitableway.

The operation of the engine is as follows: The cylinder A and core Grotate together in the same direction, but about theireccentrically-disposed axes, so that the point of contact between theperipheries of the two parts shifts around the core and causes the spacebetween the core and cylinder to increase and decrease in rear of eachpiston during each rotation of the cylinder. Steam or other motive fluidis admitted to this space just behind each piston when its inlet-passaget' registers with the admission-port of the valve 1, which occurs,preferably, when the piston is about in the position of the piston atthe right in Fig. 5. Live steam is admitted for a part revolution fromthis point and is then cut off by the mo ement of the inlet-passage 2'past the port of the admission-valve and acts expansively until theexhaust-passage 7t" in the core-section with which the piston connectsregisters with an exhaust-port it in the corejournal. This occurssomewhat before the pistons reach the position shown at the upperportion of Fig. 4 and allows the steam in advance of the pistons toexhaust before it can exert back pressure on the pistons. By thusadmitting the steam successively behind and exhausting it in advance ofthe pistons the engine is driven continuously in onedirectionforinstance, to the leftas indicated by the arrows in Figs. 4and 5.

The friction and wear in an engine constructed as described arecomparatively little, because as the core and cylinder revolve togetherthere is only the slight sliding of the one on the other, due to theeccentricity of their axes, and this is infinitely less than it is whereone part rotates while the other is stationary. Thus the friction andwear both on the ends and circular walls of the cylinder and core aregreatly reduced. The cylinder and core both rotate on relatively smallcentral journals, and the reduced speed and area of the surfaces of thecore and cylinder sliding on the journals result in decreasing thefriction and increasing the leverage of the rotary cylinder. There is nopart in the engine which slides on a surface having any considerablelength and speed. As before explained,

the pistons being fixed to the cylinder require no packing at their endsand outer edges, and the only packing necessary that is, where thepistons join the core-is effected by the rocking bearing-blocks.

I claim as my invention 1. In a rotary engine or the like, thecombination of a cylinder and a core rotatable in the same directionabout different axes, said core comprising sections which approach andrecede from each other during the revolution of the core, pistons fixedto one of said rotatable parts and loosely connected to the other part,and means for admitting fluid to and exhausting it from the spacebetween the core and cylinder, substantially as set forth.

2. In a rotary engine or the like, the combination of a cylinder and acore rotatable in the same direction about diflerent axes, said corecomprising sections which approach and recede from each other during therevolution of the core, pistons fixed to said cylinder and movablyconnected to said core-sections, and means for admitting fluid to andexhausting it from the space between the core and cylinder,substantially as set forth;

3. In a rotary engine or the like, the combination of a cylinder and acore rotatable in the same direction about different axes, said corecomprising sections which oscillate rela tive to each other about theiraxis of rotation, pistons fixed to said cylinder and each having asliding and rocking connection with one of said core-sections, and meansfor admitting fluid to and exhausting it from the space between the coreand cylinder, substantially as set forth.

4. In a rotary engine or the like, the combination of a cylinder and acore rotatable in the same direction about different axes, said corecomprising sector-shaped sections which oscillate relative to each otherabout their axis of rotation and each of which has a segmental extensionoverlapping the adjacent section, pistons fixed to said cylinder andmovably connected to said core-sections, and means for admitting fluidto and exhausting it from the space between the core and cylinder,substantially as set forth.

5. In a rotary engine or the like, the combination of a cylinder and acore rotatable in the same direction about different axes, said corecomprising sections which approach and recede from each other during therevolution of the core, pistons fixed to said cylinder and extendinginto pockets in said core-sections, segmental cylindrical blocks whichare confined in correspondingly-shaped seats in each core-section onopposite sides of and bear against the piston, and means for admittingfluid to and exhausting it from the space between the core and cylinder,substantially as set forth.

6. In a rotary engine or the like, the combination of a rotary cylinder,a core arranged eccentrically in said cylinder and comprising separatesections, a stationary journal eccentric to the axis of the cylinder onwhich said core-sections are mounted to rotate with the cylinder andoscillate relative to each other, pistons connected to the cylinder andto each of said core-sections, and means for admitting 'fluid to andexhausting it from the space be tween the core and cylinder,substantially as set forth.

7. In a rotary engine or the like, the combination of a cylinder and acore which rotate in the same direction about different axes, said corecomprising sections which oscillate relati ve to each other about theiraxis of rotation, and each core-section consisting of halves, means forpressing said halves of the coresections against opposite heads of thecylinder, pistons connecting said cylinder and coresections, and meansfor admitting fluid to and exhausting it from the space between thecylinder and core, substantially as set forth.

8. In a rotary engine or the like, the combination of a rotary cylinder,a journal arranged eccentrically in the cylinder, a core in the cylindercomprising sections provided with bearing-rings mounted side by side onsaid eccentric journal whereby said core-sections can rotate with thecylinder and also oscillate relative to each other on said eccentricjournal, pistons secured .to said cylinder and connected with saidcore-sections, and means for admitting fluid to and exhausting it fromthe space between the cylinder and the core, substantially as set forth.

Witness my hand'this 22d day of March, 1905.

WILLIAM M. HOFFMAN.

Witnesses: C. W. PARKER, E. O. HARD.

